The invention concerns a method for coordinating the operating behavior of a device for actuating a component of a motor vehicle, particularly a transmission:
Not only motor vehicle transmissions but also other components of a motor vehicle, such as clutches or valves, are increasingly being electronically controlled. To make an actuating device for such a motor vehicle component ready for production requires a testing phase in which multiple correcting parameters have to be coordinated. The expression xe2x80x9ccorrecting parameterxe2x80x9d stands for all variables that can be represented by single variables, characteristic lines, characteristic fields, tables and the like, which establish the operating characteristic of the actuating device. In automatic or automated transmissions, for example, whether the shifting characteristic is sporting or comfortable can be established by correcting parameters. The correcting parameters often have different values depending on the concrete driving situation.
In order that the actuating device provides a desired operating characteristic, an optimization is required-in the testing phase. For correcting parameters, adequate values must be found which provide the desired operating characteristic. This can be obtained, at least partly, within the scope of a simulation, but trials are likewise carried out to see how the actuating device conducts itself, to see how the actuating device actually behaves. This is especially the case in the final phase of development and testing of a new actuating device. It is important to carry out the tests on a vehicle which, in principle, already equals the production vehicles to be delivered to customers.
Only thus can it be ensured that no surprisingly irregular behavior appears in the production vehicles. For this reason, a vehicle is made available to the tester in which the actuating device to be tested is installed exactly as in the later production vehicles.
In modern vehicle manufacture, the structural combining of the vehicle electronic system with the controlled mechanical components is required more and more. Let the mechatronics be mentioned here only as a catchword.
It is thus known from the practice, e.g. in electronically controlled transmissions, to situate the control electronic system completely in the oil sump of the transmission. An arrangement of a transmission control unit in the oil sump has also been described in EP 0 697 080.
In such a transmission, the tester has no free access to the control electronic system to allow attachment of an emulation module by means of which the processor of the electronic control system could emulate the correcting parameter with different sets of parameter values. However, even in electronic control systems thus inaccessibly arranged, it is sought to give the tester the possibility of carrying out modifications of the correcting parameter xe2x80x9con boardxe2x80x9d, i.e. on the vehicle, in order that immediately thereafter he can set and can test the effects of his modifications.
The invention, therefore, is based on the problem of providing a method of the kind designated above which allows a coordination of the correcting parameters even when the control electronic system of the actuating device is installed in the motor vehicle so that there is no open access to it.
In solving this problem, the invention departs from a method for coordinating the operating behavior of a device for actuating a motor vehicle, especially a transmission, wherein the device comprises actuators for the motor vehicle components, the same as an electronic control unit which controls the actuators according to predetermined correcting parameters represented by data elements wherein in the method, an initial data element is first assigned to each correcting parameters. Then the operating behavior of the actuating device is tested with the initial data elements of the correcting parameters and on the strength of that, depending on the test results, new data elements are assigned at least to a part of the correcting parameters.
According to the invention, it is provided that each initial data element be stored in a programmable memory for constant values of the control unit and, with each stored initial data element, an additional blank address memory section in the memory for constant values be associated, that for each new data element, an addressable new data memory section and an appertaining address memory section is made available in which the new data element is stored, that the memory address of each new data element be written in the address memory section of the appertaining initial or reference data element, and that the control unit at each access tests on a correcting parameter, whether in the address memory section associated with the data element of this correcting parameter a memory address has been written and in the affirmative accesses the new data memory section addressed by the memory address, otherwise accesses the initial or reference data element of the correcting parameter.
The invention is based on the fact that the storing structure of the data elements is predetermined in a memory for constant values and cannot be changed by writing cycles. Therefore, the invention proposes to copy the storing structure of the original data elements and to write new data elements in the copy of the storing structure. In the original data section is written, at the same time a corresponding address reference which points to the copied storing structure with the new data elements.
An essential advantage of the inventive method is that it can be recursively applied. The whole process, i.e. the copy of the storing structure of the old data memory section plus a new deposit of the copied storing structure with new data elements with address reference from the old data memory section, can be consecutively repeated until the available blank data memory section is absolutely used up.
The expression data element stands here for the representation of a correcting parameter according to data technology. It is obvious that the variable of a data element and the inner data organization thereof can vary to a great extent, depending on whether the data element represents an individual value or whether it represents complex structures, such as a table or a characteristic field. It is absolutely possible that one data element be organized as data field consisting of a multiplicity of data words, but a data element can also consist only of a single data word.
When speaking of an initial data element, thereby it is understood aa a data element whose contents serve as point of departure for the subsequent coordination. The data contents of an initial data element can be arbitrarily established by the test person, e.g. according to experimental values. It can also form the result of a previous coordination procedure within the scope of which a rough coordination of the correcting parameters was obtained.
In the inventive solution, the initial data elements are written in a programmable constant memory value of the control unit. In the current electronic control systems, a constant memory value is regularly already available, namely, in the form of a program memory for a microprocessor program. The program memory can be dimensioned so as to offer sufficient memory space at least for the initial data elements beyond the control program. In this manner, it is possible (at least for the initial data elements) to eliminate an additional memory module, but it is obvious that the initial data elements can be written also in a separate memory module.
Today In microelectronic control circuits, constant value memories electrically erasable EEPROMS or flash EEPROMS are customarily used. Even though, in such constant value memories, it is basically possible to change the memory contents by erasing and a subsequent new entry, those superscribing processes often cannot be carried out without limit and frequently not within a sufficiently short time. For this reason, according to the invention, when a correcting parameter has to be updated, there is no writing over its initial data element which is left in the constant memory value. The new data element of the correcting parameter concerned is stored in a different place. It would now be impracticable to change the control program of the control unit in the sense that when the correcting parameter concerned is called, it immediately accesses the new data element. Instead of this, the control program is left unchanged, where in the future, when the correcting parameter is called, it first branches to the memory address of the initial data element. To communicate to the control program that the initial data element of a correcting parameter no longer applies, the invention refers back to the expedient of the address reference. The address reference is written in the address memory section of the relevant initial data element. At the start of the coordination procedure, the address memory section, associated with each initial data element, is blank. The blank state is conveniently the state of the memory cells of the constant memory value after an erasing operation. If a new data element is assigned to a correcting parameter, the memory address in which the new data element has been stored is written in the address memory section of the appertaining initial: data element.
Each time a correcting parameter is called, the control program first examines first the address memory section associated with the initial data element of the correcting parameter. If the address memory section is blank, this tells the control program that for the correcting parameter concerned the initial data element still applies. Accordingly, it reads the initial data element and uses it in its future operations. On the contrary, if the address memory section contains an address reference (pointer), the control program knows that to the correcting parameter concerned a new data element has been assigned and that the new data element is to be found in the new data memory section identified by the pointer.
In the invention, additional memory space beyond the initial data elements is only needed forthose correcting parameters to which new data elements have been assigned. In the practice, it has been found that the additional memory space needed can often be covered by a reserved memory which is usually held in the memory modules of current electronic control systems. Thus It is not unusual that in EEPROMS or flash EEPROMS, which serve as program memory, a reserve of blank memory space is available to use for other purposes which occasionally extends to the magnitude range of the memory space required for the program itself.
One development of the invention provides that each new data element be stored in a blank new data memory section of the constant memory value.
It is also alternatively conceivable, however, that each new data element be stored in a new data memory section of a read-write memory of the control unit. This read-write memory can be a RAM memory which simultaneously serves as data memory for the variables appearing when working off a microprocessor program. But it is also possible to provide an additional RAM module in which the new data elements are exclusively stored.
The inventive method is not only adequate but, in particular, when the control unit is installed in the vehicle inaccessibly concealed and communication by data technology is only possible from outside with the components of the control unit by guided out data communication lines. In this case, it is easily possible for a test person or an applicator (i.e. a person who applies new data elements for the correcting parameters) to coordinate the correcting parameters while sitting in the vehicle, e.g. by means of an application unit, which is carried in the passenger compartment of the vehicle and can be attached to the guided out communitation lines of the control unit. The application thus can directly examine on the vehicle how the application of a new set of data elements works in the practice.
Until the desired operating behavior of the actuating device appears, it will not be necessary to apply new data elements for individual correcting parameters, therefore the operating behavior of the actuating device is repeatedly examined and after each examination, depending on the current examination result, at least one part of the correcting parameters is updated, as may be needed, by assignment of a currently new data element.
As long as a constant memory value with enough storage capacity is available, upon each updating of a correcting parameter its current new data element can be stored in a blank new data memory section of the constant memory value, an additional blank address memory section in the constant memory value is further associated with the new data element. The memory address of the new data element is written in the address memory section of the last applicable data element of the correcting parameter prior to the updating.
In this development, an interlinked recursive access to the actually valid. data element of a correcting parameter results. The interlinkage is ensured by the address memory section which is associated with every new data element. In each data elementxe2x80x94be it the initial data element or a subsequently applied data elementxe2x80x94the control unit (or the control program) tests whether the address memory section associated with the current data element is blank or contains a pointer. In the first case, the control unit knows that the interlinkage is at the end and accesses the concerned data element. In the latter case, the control unit knows that there is at least one further, subsequently applied data element for the correcting parameter concerned and branches to the next data element identified by the pointer. Here again an examination of the appertaining address memory section first takes place. By interlinkage by means of pointers the applicator is enabled subsequently to program, in new data elements the constant memory value without having to carry out erasures in the constant memory value. For reasons of security, the subsequent programming is conveniently carried out while the vehicle is stationary.
In the course of the coordination procedure for individual correcting parameters, if a plurality of new data elements has to be subsequently programmed, it can occur that the available memory space in the constant memory value be some time or other used up. In the case of an erasable, especially electrically erasable, constant memory value can be established by correcting parameters, a complete updating of the memory contents can then be carried out wherein the last valid data elements of the correcting parameters, i.e. the data elements standing at the end of the recursion, are conveniently programmed in as new initial data elements. The applicator can advantageously carry this out by means of an application unit carried along in the vehicle. It has been found in the practice that in the usual procedure requirement of an update is to be taken into account once a day.
If the new data elements have been written in a read-write memory, it is not necessary to associate with the new data elements also address memory sections for pointers, since it is possible in read-write memories to write upon as often as desired and quickly enough. It is then advisable that upon each updating of a correcting parameter, the currently new data element is written upon the last data element valid prior to the updating, provided it is stored in the read-write memory. Thus only the memory space must be held ready in the read-write memory for each correcting parameter would be necessary for a single data element of the correcting parameter concerned. This results in a very small space being altogether required.
At any time, in order to have a general view as to how much memory space is still available for new data elements, it is advisable that a pointer in the control unit, be maintained which points to the beginning of a blank reserved memory still available for registering new data elements in the constant memory value or the read-write memory and that upon each new data element registered in the reserved memory the pointer is updated accordingly. When a new data element is written in the reserve memory and accordingly the reserved memory becomes smaller, this pointer corresponds to the memory address of the new data element and can be thus written as address reference in the address memory section of the previous data element in the recursion.
A preferred if not even exclusive sphere of utilization of the inventive method is the electronic control of a motor vehicle transmission wherein the electric and electronic components of the control unit are collected in an electronic assembly, as a rule tightly packed, and the electronic assembly is at least partly immersed in the oil sump of the transmission. The electronic assembly can especially be designed in hybrid construction, for example, with a ceramic base plate upon which the different components are mounted by hybrid technology.
Controlled by the control unit, the actuators for the motor vehicle components can be of different kinds depending on the configuration of the motor vehicle components. They can comprise electromotors, hydraulic actuators, valves, pumps, or the like.